Original scientific paper

https://doi.org/10.17559/TV-20150513090840

Failure analysis of bolted joint for the column of an aerial platform

Branislav Rakićević ; University of Belgrade, Faculty of Mechanical Engineering, Kraljice Marije 16, 11120 Beograd 35, Republic of Serbia
Miloš Maneski ; University of Belgrade, Faculty of Architecture, Bulevar Kralja Aleksandra 74, 11000 Beograd, Republic of Serbia
Saša Mitić ; University of Belgrade, Faculty of Mechanical Engineering Kraljice Marije 16, 11120 Beograd 35, Republic of Serbia
Goran Vorotović orcid.org/0000-0003-2606-7142 ; University of Belgrade, Faculty of Mechanical Engineering Kraljice Marije 16, 11120 Beograd 35, Republic of Serbia
Dražan Kozak orcid.org/0000-0001-5245-4686 ; J. J. Strossmayer University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Trg Ivane Brlić-Mažuranić 2, HR-35000 Slavonski Brod, Croatia
Marko Katinić ; College of Slavonski Brod, Technical Department, Dr. Mile Budaka 1, 35000 Slavonski Brod, Croatia

Abstract

This paper focuses on the identification of failure causes of a bolted joint used for the bedding of a primary column of an aerial platform. The tests conducted to determine chemical composition and mechanical properties have confirmed the 12.9 grade of the bolts. Also, mechanical properties tests and metallographic examination did not indicate any hidden defects caused by heat treatment (e.g. decarburisation etc.). On the other hand, visual and metallographic examination of cross-section as well as electron microscope scanning confirmed fatigue fracture of the bolts. Therefore, further analyses were done to check the dimensioning and the installation of the bolts. The effects on stress states in the bolts are presented from the standpoint of rated operating regimes, stiffness of joined elements, lubrication conditions of thread surfaces and temperature incompatibility between the bolts and elements being joined. Pre-tightening torque value incompatible with lubrication conditions was found to be the main factor that led to high stress values that initiated and later intensified the fatigue process which ended in fatigue failure of the bolts.

Keywords

bolted joint lubrication; failure of bolts with high mechanical properties

Hrčak ID:

167487

URI

https://hrcak.srce.hr/167487

Publication date:

13.10.2016.

Article data in other languages: croatian

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